AbstractReconstruction of the fluid flow history during Laramide forelandfold and thrust belt development in eastern Mexico: cathodoluminescence and δ18O-δ13C isotope trends of calcite-cemented fractures
Abstract
The Cordoba Platform in eastern Mexico has been studied to reveal the deformation and fluid flow history of the Laramideforeland fold and thrust belt (FFTB) and to define the controlling parameters on hydrocarbon reservoir development. Cathodoluminescence (CL) and stable isotope analyses of calcite-cemented strata and fractures point out different episodes of fluid flow that have been coupled to the deformation agenda. This study reveals an early burial phase with host-rock-buffered fluids and overpressures resulting in hydraulic fractures that relate to foreland flexuring with additionally local karst development. Layer-parallel shortening is accompanied by expulsion of formation waters that are no longer host-rock-buffered. Subsequent folding and thrusting led to opening of vertical features and finally to the influx of meteoric fluids and telogenetic karst development in the outcropping part of the FFTB. In the tectonic front, thrust emplacement was associated with intensive fracturing and subsequent oil migration.
References (6)
- FerketH. et al.
Fluid migration placed into the deformation history of fold-and-thrust belts: an example from the Veracruz basin (Mexico)
J. Geochem. Explor.
(2000) - TavarnelliE.
Structural evolution of a foreland fold-andthrust belt: the Umbria-Marche Apennines, Italy
J. Struct. Geol.
(1997) - CampbellK.A. et al.
Ancient hydrocarbon seeps from the Mesozoic convergent margin of California: carbonate geochemistry, fluids and palaeoenvironments
Geofluids
(2002)
Cited by (31)
A comparison of hydrothermal events and petroleum migration between Ediacaran and lower Cambrian carbonates, Central Sichuan Basin
2023, Marine and Petroleum GeologyHydrothermal minerals and associated organic matter have been frequently found in the Ediacaran and lower Cambrian carbonate reservoirs, separated by internal shale source rocks, in the Central Sichuan Basin. This work provides a thorough comparison of petrography, geochemical signatures, fluid inclusions and ages between the hydrothermal minerals in the Ediacaran Dengying Formation (Fm) and the lower Cambrian Longwangmiao Formation. This comparison leads to a better understanding of the behaviour and migration history of hydrothermal fluids and petroleum. During the Ediacaran–Cambrian transition, the flux of silicon-rich hydrothermal fluid triggered by seafloor-related volcanic events, resulted in the exclusive occurrence of silicification in the Dengying Fm. During P3–T3, two different hydrothermal systems were found in the Dengying and Longwangmiao formations. The hydrothermal fluids in the Dengying reservoirs were dominated by a mixture of basement-derived Mississippi Valley Type [MVT] ore fluids and shale-derived oil-bearing brines, while those in the Longwangmiao Fm were mainly the oil-bearing brines. The upwards migration of the MVT ore fluids, characterized by very hot, saline, radioactive and Eu-rich conditions, was promoted by the activity of the Emeishan mantle plume 259.4–248 Ma and then blocked by the lower Cambrian shales and trapped only within the underlying Dengying reservoirs. The expulsion of the warm, less saline and moderately radioactive brines and oil was induced by thermal maturation of the organic-rich shales, which might have occurred over a longer duration (261–218.7 Ma). During 170.7–125.8 Ma (J2–K2), the combined effects of the overmature source rocks and Yanshanian tectonic compression facilitated the migration of much hotter shale-derived brines, as well as gas hydrocarbons, across the Ediacaran to lower Cambrian carbonate reservoirs. This comparative study provides some insights into the behaviour of hydrothermal fluids and petroleum in carbonates with internal organic-rich shales.
Multiple fluid flow events and diversity of hydrothermal minerals in Neoproterozoic to lower Paleozoic carbonate reservoirs, Tarim Basin, NW China
2022, Journal of Asian Earth SciencesContrasting mineral assemblages have been frequently found in Neoproterozoic-lower Paleozoic carbonate reservoirs along high-angle faults in the Tarim Basin. However, the reason for the change in mineral types over time is poorly constrained. Field and petrographic observations, fluid inclusion microthermometry, rare earth element (REE) and C, O and Sr isotope analyses are used to constrain the changes in water chemistry and fluid flow during the development of the mineral assemblages. During the Middle Devonian-early Carboniferous, the flux of hydrothermal fluids from Neoproterozoic sandstone layers, linked to the activity of NE–SW-trending strike-slip faults, resulted in extensive silicification. The silica-bearing fluids were hot (128.1–209.4 °C), saline (17.1–21 wt% NaCl eq.) and enriched in radiogenic strontium and showed no link to large-scale petroleum migration. During the Permian, a regional thermal anomaly induced the expulsion of hydrocarbon-bearing hydrothermal fluids from lower Cambrian shales, where Mg2+, 87Sr and F− were derived via the transformation and leaching of clay minerals. A more significant in situ source of Mg2+ was the dolostone interval, as the migrating fluids contributed to the precipitation of saddle dolomite with high Th values (82–176.4 °C) and salinities (15–21.4 wt% NaCl eq.), negative δ18O values and radiogenic Sr compositions. The succession of saddle dolomite followed by fluorite with similar Th values, salinities and 87Sr/86Sr ratios indicates a Mg2+ deficit and increased dissolved calcium activity in the same parent fluid system, which facilitated the breakdown of MgF− and combination of Ca2+ and F−. Subsequently, cooling and desalination of the hydrothermal fluids occurred, which was induced by the infiltration and mixing of meteoric water related to the compression and uplift of the north-western flank of the Tarim block. These processes resulted in the precipitation of milky white calcite (Cal 1) with similar oxygen and strontium isotope compositions but wider ranges of Th (82.1–154 °C) and salinity (3.4–16.9 wt% NaCl eq.) than those of the saddle dolomite and fluorite. The lateral flow of hydrothermal fluids through suitable layers, such as bed interfaces, permeable aquifers and karstic units, facilitated the formation of stratabound mineral deposits away from the feeding faults. The termination of hydrothermal mineralization was marked by the precipitation of brown calcite (Cal 2), whose meteoric origin has been proven by the combination of its reddish staining, oscillatory luminescent zonation and low δ18O values. This integrated study approach improves the understanding of the diversity of exotic mineral assemblages in carbonate hosts and the evolution and migration of hydrothermal fluids connected to late Paleozoic tectonism.
From hydroplastic to brittle deformation: Controls on fluid flow in fold and thrust belts. Insights from the Lower Pedraforca thrust sheet (SE Pyrenees)
2020, Marine and Petroleum GeologyWe present a multidisciplinary study to decipher the controls of deformation on fluid flow regime in fold and thrust belts using the Lower Pedraforca thrust sheet in the SE Pyrenees as an example. We integrate field-based and petrographic observations and geochemical and geochronological data to differentiate seven types of fractures, eight types of calcite cement (Cc1 to Cc8) and two sets of stylolites during the deformation stretching the studied thrust sheet. During syn-sedimentary hydroplastic normal faulting affecting poorly consolidated Upper Cretaceous and Eocene syn-orogenic sediments, calcite cement did not precipitate. During burial, bed-parallel stylolites formed and Cc1 and Cc2 precipitated from formation waters in a closed palaeohydrological system. During the layer-parallel shortening, Cc3 precipitated from formation waters (~+5.4‰ VSMOW) with 87Sr/86Sr ratios of 0.707922 and at ~70 °C. Cc4 precipitated from formation waters recording different burial conditions, as the up to 4‰ dispersion in δ18O of this cement suggests. Contrarily, during folding and thrusting, Cc5 to Cc7 precipitated in an open palaeohydrological system. Cc6 precipitated from formation waters (~+5‰ VSMOW), with 87Sr/86Sr ratios of 0.707817 and at ~75 °C. These fluids carried hydrocarbons and probably interacted with Upper Triassic evaporites. An 87Sr/86Sr ratio of 0.708230 for Cc5 indicates that formation waters also interacted with clays within continental deposits. During this period, stylolites formed in relation to faulting, and previous hydroplastic normal faults reactivated as reverse and strike-slip faults allowing fluid flow. Cc7 precipitated after Cc6, also from fluids in isotopic disequilibrium with their adjacent host rock. The fluid system continued open during the Oligocene, when Cc8 precipitated in normal faults affecting syn-orogenic conglomerates deposited during the reactivation of the Lower Pedraforca thrust sheet. The influence of deformation on fluid flow observed in the Lower Pedraforca thrust sheet is similar to that observed in other fractured areas worldwide.
Link of laminated crusts associated with pisolites to sea-level change: A case study from the Ladinian (Middle Triassic) Longtou Formation, Guizhou, China
2019, Sedimentary GeologyCitation Excerpt :Two fracture-filling calcite samples from PZC section display rather negative δ13C (−3.32‰ to −2.83‰) values (Fig. 7), indicating that the fluids responsible for the formation of the large calcite crystals were enriched in 12C (Gao et al., 1992). The non-luminescent fracture-filling calcite could be meteoric (Ferket et al., 2003) or hydrothermal (Braithwaite and Rizzi, 1997) in origin. Given the continued deposition of sediments (>2500 m) overlying the Ladinian Longtou Formation until major deformation in Guizhou in mid-Cretaceous (Enos et al., 2006), the Longtou Formation is expected to undergo burial diagenesis including the fractures to some extent.
The nature (depositional or diagenetic) of laminated crusts associated with pisolites is still in debate, which hampers the interpretation of sea-level change on carbonate platforms. The Ladinian Yangtze platform margin, formed by the Longtou Formation, contains abundant laminated crusts associated with pisolites, providing an opportunity to decode their formation in response to sea-level variations. There, individual laminae are formed of isopachous radiaxial fibrous calcite (RFC) crystals. The RFC displays strong undulose extinction and orange-red or dull red cathodoluminescence. The pisolites (vadoids) coexisting with the laminated crusts are characterized with inverse graded bedding, stalactitic cements, and red luminescence or non-luminescence. The laminated crusts and associated pisolites have δ18O values ranging from −10.56‰ to −3.83‰ and from −7.12‰ to −6.33‰, respectively, which are more negative than that of the Ladinian normal seawater. They also share similar rare earth element and yttrium (REE + Y) distribution patterns, with enriched heavy rare earth element (HREE), enriched Y element, true negative Ce anomalies, and Y/Ho ratios between 34 and 51. Detailed petrographic and geochemical analyses indicate that the laminated crusts and associated vadoids formed in caves in response to alternating meteoric water and seawater, with the fluctuating water table resulting in their mixed deposition. The preservation of laminated crusts and vadoids in the Longtou Formation implies that they formed during a period of overall sea-level transgression, which was punctuated by sea-level regression and allowed formation of cave fillings. Our results suggest that laminated crusts present in ancient carbonate successions may indicate the positions of subaerial exposure related to sea-level regressions.
The Cretaceous-Paleogene Mexican orogen: Structure, basin development, magmatism and tectonics
2018, Earth-Science ReviewsThe Mexican orogen is the expression in Mexico of the Cordilleran orogenic system. The orogen extends the length of Mexico, a distance of 2000 km from the state of Sonora in the northwest to the state of Oaxaca in the south. The Mexican orogen consists of (1) a western hinterland of accreted oceanic basinal rocks and magmatic arc rocks generally known as the Guerrero volcanic superterrane, (2) a foreland orogenic wedge, commonly termed the Mexican fold and thrust belt (MFTB), composed of imbricated and folded Upper Jurassic-Lower Cretaceous carbonate rocks and Upper Cretaceous foreland-basin strata, and (3) an assemblage of variably folded and inverted Late Cretaceous to Eocene foreland basins that lie northeast and east of the MFTB. The Mexican orogen encompasses the entire country, spanning several physiographic provinces and deformational domains that display both thin-skinned and thick-skinned structural styles determined by inherited crustal structure and contrasting pre-kinematic sedimentary sections. The orogen contains kinematic characteristics of both the Sevier and Laramide orogens in the United States (U.S.), and deformation in the Mexican orogen spanned the deformational history of those U.S. orogens. The overall trend of the Mexican orogen is NW-SE, although it displays local trend variations. At presently exposed levels, the orogen consists of folded and reverse-faulted Mesozoic-Eocene strata. Lower Cretaceous strata of the deformed foreland are dominated by carbonate rocks, whereas time-equivalent strata in the hinterland consist of deformed plutons belonging to one or more magmatic arcs, as well as turbidites, pillow lavas and altered mafic rocks deposited in an offshore basin prior to consolidation of fringing arc systems to mainland Mexico. Upper Cretaceous syntectonic strata of the foreland orogenic wedge constitute siliciclastic turbidite successions that grade eastward to carbonate pelagites of the distal foreland basin, which was starved of siliciclastic sediment input. Uppermost Cretaceous and Paleogene strata of the foreland basin constitute a shelfal, deltaic and coastal plain fluvial succession in northeastern Mexico and a succession of turbidites in the Tampico-Misantla basin east of the MFTB.
Structural geometry of the orogen was controlled by the spatial distribution of pre-Cretaceous crustal elements, such as Jurassic extensional basins and basement blocks, and detachment horizons at varying stratigraphic levels, as well as the direction of structural vergence, which is dominated by NE-directed tectonic transport throughout the belt. Jurassic evaporite horizons and Upper Jurassic carbonaceous shale units provide detachment surfaces in some parts of the orogen. The structural style of the MFTB is generally thin-skinned, although high-angle faults are present at several localities, where the steep faults cut thin-skinned, shallowly-dipping faults, detachment horizons and associated folds. Strain magnitude decreases toward the foreland and generally satisfies critical wedge predictions. Values of shortening > 70% are present in the hinterland of central Mexico; these decrease systematically to values < 15% to the front of the fold belt where upper Eocene onlap successions in the Gulf of Mexico coastal plain unconformably overlie deformed strata of the orogenic wedge. Exceptions to this pattern of regional shortening values are well documented and are related to lateral variations in mechanical properties caused by facies variations, notably massive platformal carbonates as contrasted with thinly-bedded basinal carbonates.
Shortening history in the Mexican orogen approximately spanned Late Cretaceous-Eocene time. Deformation timing has been constrained using Ar-Ar systematics on illite generated by layer-parallel slip in the limbs of chevron folds. Estimates of deformation timing are in good agreement with the age of synorogenic sedimentary successions, and with ages of syn-tectonic plutons. Published data from central Mexico suggest episodic pulses of deformation between 93–80 Ma, 75–64 Ma and 55–43 Ma, which postdate the closure of the Arperos basin. Each of these shortening events affects rock units lying progressively farther to the east to yield a temporal eastward advance of deformation and sedimentation. Effects of successively younger shortening were superimposed on the westernmost exposures of the thrust belt and are evidenced on a map scale by abrupt trend variations in orogen-interior folds, compared to generally linear or broadly arcuate axial traces of frontal folds.
Although potential tectonic mechanisms for shortening in the Mexican orogen remain debated, our analysis indicates that orogenic wedge development took place in a retroarc setting that postdated consolidation of the hinterland oceanic assemblages, which lay offshore western Mexico during Albian time. Orogen development followed a protracted period of early Mesozoic extension that affected most of the Mexico due to the combined effects of Laurentia-Gondwana separation and long-term Triassic-Jurassic rollback of a paleo-Farallon plate. Slab rollback ultimately resulted in the development of a marginal basin, the Arperos basin, between a rifted Late Jurassic magmatic arc and mainland Mexico. Initial shortening in the Mexican orogen, which followed Arperos basin closure and Guerrero superterrane accretion by ~ 5–10 Ma, was coeval with voluminous magmatism on the Pacific margin of Mexico, drowning of the western carbonate platforms and onset of foreland-basin sedimentation in Cenomanian time. Subduction of the Farallon slab from early Late Cretaceous to Eocene time was thus the primary driving mechanism of shortening in the Mexican orogen.
Reaction-induced porosity fingering: Replacement dynamic and porosity evolution in the KBr-KCl system
2018, Geochimica et Cosmochimica ActaIn this contribution, we use X-ray computed micro-tomography (X-CT) to observe and quantify dynamic pattern and porosity formation in a fluid-mediated replacement reaction. The evolution of connected porosity distribution helps to understand how fluid can migrate through a transforming rock, for example during dolomitization, a phenomenon extensively reported in sedimentary basins. Two types of experiment were carried out, in both cases a single crystal of KBr was immersed in a static bath of saturated aqueous KCl at room temperature and atmospheric pressure, and in both cases the replacement process was monitored in 3D using X-CT. In the first type of experiment a crystal of KBr was taken out, scanned, and returned to the solution in cycles (discontinuous replacement). In the second type of experiment, 3 samples of KBr were continuously reacted for 15, 55 min and 5.5 h respectively, with the latter being replaced completely (continuous replacement). X-CT of KBr-KCl replacement offers new insights into dynamic porosity development and transport mechanisms during replacement. As the reaction progresses the sample composition changes from KBr to KCl via a K(Br, Cl) solid solution series which generates porosity in the form of fingers that account for a final molar volume reduction of 13% when pure KCl is formed. These fingers form during an initial and transient advection regime followed by a diffusion dominated system, which is reflected by the reaction propagation, front morphology, and mass evolution. The porosity develops as fingers perpendicular to the sample walls, which allow a faster transport of reactant than in the rest of the crystal, before fingers coarsen and connect laterally. In the continuous experiment, finger coarsening has a dynamic behaviour consistent with fingering processes observed in nature. In the discontinuous experiment, which can be compared to rock weathering or to replacement driven by intermittent fluid contact, the pore structure changes from well-organized parallel fingers to a complex 3D connected network, shedding light on the alteration of reservoir properties during weathering.